I agree the rhomboids best for crossing heavy terrain. But i Always wondered for all its good points wether the FT was suitable for the task of crossing terrain and (widened) trenches at the western front

Who besides Britain/Commonwealth (and white/red Russia) used WWI rhomboid tanks after the war? I suspect Whippets had a wider career.

If post war sales are an indicator of success, I guess nothing touches the FT-17. Is there a region of the world that hasn't had those at one time or another? :-)

Japan purchased 1 female model and it reached Yokohama in 1918 and from there, it was transported around in Japan, and was inspected and did experiment runs. During WW2, it was kept at Yasukuni Shrine but after the war, it's not known what happened to it.

How did the trench crossing ability of FT-17's or Whippets compare to the rhomboids? Did they have problems coming forward in the second wave after the rhomboids had cleared a hole through the trenches?

Rhomboid tanks and similar where niche machines and required significant support to move, etc. The FT-17 really allowed the tank to try new and different challenges and were logistically more efficient, The Whippet with turret(s) would also have been a versatile design, but lacked suspension and a reliable steering method.

Putting a turret on top of a rhomboid [2 pdr on TOG1] does not make the tank any less rhomboid. We should also add to TOG1 (1940), the FCM Char 2C(1919), the German Grosstrakto/Neubaufahrzueg (1926ff), even the Rus T35.

Markus, the 3-inch turret was carried on TOG2, which had a peculiar suspension taking it out of the rhomboid class.

Putting a turret on top of a rhomboid [2 pdr on TOG1] does not make the tank any less rhomboid. We should also add to TOG1 (1940), the FCM Char 2C(1919), the German Grosstrakto/Neubaufahrzueg (1926ff), even the Rus T35.

Markus, the 3-inch turret was carried on TOG2, which had a peculiar suspension taking it out of the rhomboid class.